Microfluidic Fabrication of Hierarchical-Ordered ZIF-L(Zn)@Ti 3 C 2 T x Core-Sheath Fibers for High-Performance Asymmetric Supercapacitors.

We report hierarchical-ordered ZIF-L(Zn)@Ti 3 C 2 T x MXene core-sheath fibers, in which a ZIF-L(Zn) nanowall array sheath is grown vertically on an anisotropic Ti 3 C 2 T x core by Ti-O-Zn/Ti-F-Zn chemical bonds. Through highly efficient microfluidic assembly and microchannel reactions, ZIF-L(Zn)@Ti 3 C 2 T x exhibits well-developed micro-/mesoporosity, ordered ionic pathways, fast interfacial electron conduction and large-scale fabrication, significantly boosting charges dynamic transport and intercalation. The resultant ZIF-L(Zn)@Ti 3 C 2 T x fiber presents large capacitance (1700 F cm -3 ) and outstanding rate performance in a 1 M H 2 SO 4 electrolyte. Additionally, ZIF-L(Zn)@Ti 3 C 2 T x fiber-based solid-state asymmetric supercapacitors deliver high energy density (19.0 mWh cm -3 ), excellent capacitance (854 F cm -3 ), large deformable/wearable capabilities and long-time cyclic stability (20 000 cycles), which realize natural sunlight-induced self-powered applications to drive water level/earthquake alarm devices.